In this work,bio-inspired concepts,including a Self-Healing (SH) and super hydrophobic structure,were used to produce slow-release of urea fertilizer.Following a bottom-up process,an SH layer on the urea granule was produced from a combination of two natural waxes,palm and cauba,and fabricated by a hot-melt coating process in a pan coater.Another layer for super hydrophobicity was formed by a deposition of submicron-wax and carbon black particles on the SH layer to create a micro-nanostructure during coating.After the heat treatment,a smooth coating and even deposition of waxes throughout the urea surfaces were obtained.The properties of the waxes,a healing mechanism,and releasing profiles were examined using an optical microscope.After cracking of the coated urea surface,the intrinsic self-healing behavior was stimulated by heating the samples above 45 ℃C,corresponding to high ambient daytime temperatures.Air-trapping behavior was observed at the interphase of the water and coated urea,creating super hydrophobic granule surfaces which act as an invisible layer for water-penetration protection.The releasing profiles of the coated urea in soil revealed that the releasing periods could be significantly extended to four-times longer than those of the uncoated urea.